Code Insights: Fix "add insight" insight creation flow
Created by: vovakulikov
Closes https://github.com/sourcegraph/sourcegraph/issues/31303
Test plan
- Go to your private/org/global (any custom user-created dashboard actually)
- Click "Add Insights" button
- Click on the "create insight" link below the search field in the "Add Insights" modal UI
- Create any type of insight
- See that you have been redirected on the dashboard you came from
- See that your newly created insight is presented on the current dashboard